TEI and DocBook interleaved

We want a TEI document which allows DocBook elements to appear, e.g. for describing GUIs in inline contexts

We also want TEI structured inline elements to appear inside the DocBook GUI elements:

<TEI  xmlns="http://www.tei-c.org/ns/1.0"
       xmlns:dbk="http://docbook.org/docbook-ng">
....
   <text>
      <body>
<p>The button on our web page has the current date:
<dbk:guibutton>
<date 
 calendar="Julian" value="1732-02-22">
Feb. 11, 1731/32, O.S.</date>
</dbk:guibutton>
or at least the date on which we last updated it.</p>
     </body>
   </text>
</TEI>